Police raided the offices of the Papuan Customary Council, the top representative body for indigenous Papuans in the provincial capital Jayapura, arresting 15 activists and damaging equipment, council secretary general Leonard Imbiri told AFP.

"They trashed the offices, destroyed two computers and they burnt down a traditional hut behind the building," Imbiri said.

Vico Yeimo, the head of the West Papua National Committee, said the activists were arrested on suspicion of trying to organise a rally in the city, an earlier request for which was turned down by police.

Papua police chief Bagus Eko Danto refused to confirm the arrests or the damage to the assembly.

More than 10,000 activists took to the streets in the towns of Nabire and Wamena to call for Papuans to boycott national legislative elections next week and in solidarity with the establishment abroad of an international pressure group called International Lawyers for West Papua, activists said.

Around 12,000 Papuans led by 50 men in traditional penis gourds and feathers marched though Nabire with no arrests, local church activist Yones Douw said.

"Our demand is that Papuans don't take part in the election because we are not part of Indonesia," he said.

Papua, which sits on the western end of New Guinea island, was officially incorporated into Indonesia in a 1969 UN-backed vote of tribal elders widely seen to have been stage-managed.

Support for independence is high among indigenous Papuas, who are Melanesians ethnically distinct from other Indonesians. The government restricts access to the area by foreign media.